Thomas j



(No Model.)

No. 556,342. Patented Mar. 17, 1896. f

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WITN ESS ES %Z% UNITED STATES PATENT OFFICE.

THOMAS J. FAY, OF NEW YORK, N. Y.

ELECTRIC-MOTOR RH EOSTAT.

SPECIFICATION forming part of Letters Patent No. 556,342, dated March 17, 1896.

Application filed. December 12, 1895. Serial No. 571,879. No model.)

To all whom it may concern.-

Be it known that I, THOMAS J. FAY, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Electric-Motor Rheostats, of which the following is a full, clear, and exact description.

This invention relates to electricmotor starting-boxes or rheostats, the object being to construct and mount the rheostat in such a way that it will have a large radiatingsurface and will be constantly ventilated while in use.

The invention consists in general of a suitable frame in which is placed the resistance material, the frame being preferably mounted upon or to rotate with the shaft of the electric motor which the resistance controls. In conjunction with this rotating frame is a series of contacting-surfaces respectively connected with the sections of the rheostat and two sliding contacts, one of which remains constantly in contact with one of the moving surfaces, while the position of the other is variable thereon, and means for adjusting the moving contact in proportion to the speed of the motor.

The invention will be described in detail with reference to the accompanying drawings, in which- Figure 1 is a side elevation of an electric motor, its starting-rheostat, and controlling devices therefor. Fig. 2 is a side elevation of the rheostat.

Referring to the drawings by letter, A represents an electric motor, and u its armatureshaft. The shaft is extended beyond the pillow-block at one end, and carries thereon a cylindrical frame B, resembling a pulley in external appearance. This frame is made rigid upon the shaft and is provided internally with suitable framework 1), upon which is strung wires or wire coils Z), constituting the starting-resistance of the motor. The construction of the internal framework upon which the wire is supported and the method of insulating the wire to prevent short circuits, &c., is of any suitable character, the only requirement being that the frame shall be as open as possible to allow of a free circulation of air through it, especially when it is rotated.

The main frame of the rheostat B may, of course, be polygonal in shape, but the cylindrical form described will answer the purpose best.

Adjacent to the rheostat-frame and mounted eccentrically upon the same shaft is a series of contacting-rings c, suitably mounted upon a cylinder, and effectually insulated from each other by alternately-disposed layers of mica or other similar material. These rings correspond to the ordinary series of stationary contacts provided with every adjustable rheostat, and therewith each of them is connected with one section of the wire or coils in the main frame, it being understood that the said wire or coils is divided up into as many sections as there are rings 0. Adjacent to the rings is mounted in a fixed position an arm cl, carrying at each end rods d and (1 Rod d has fixed to its extremity a brush holder in which is located a brush 6, resting against the first ring of the series 0. Upon rod (1 is mounted a brush-holder (1 which is adapted to slide along the rod so as to carry its brush 6 successively over the rings 0 from one end of the series to the other. tion is imparted to the brush-holder d by means of a centrifugal device F. This is constructed on the principle of the usual ballgovernor, its shaft being geared to the shaft of the motor, as shown at f, and the balls f standing outward more and more as the speed of the motor increases. This movement of the balls is communicated to the sliding collar f which is connected by a suitable system of levers f with the movable brush-holder d The arrangement is such that when the motor is not running the brush e willbe on the ring of the series 0, at which point the entire resistance will be in circuit between the two brushes, it being understood of course that one of the main feeding-wires of the motor connects with one brush, while the other connects with the other brush. The size or quantum of the entire resistance will be such that the motor will start slowly at the full load when the entire resistance is in circuit. The motor having started, the resistance is gradually cut out by the governor F until the ma- This mochine is running at full speed. The device therefore acts automatically. It will be seen that this resistance when in operation creates a current of air which maintains it at a low temperature. It is obvious that the rheostat with its series of rings maybe mounted upon any rotating shaft other than the motor-shaft, but the governor which controls it must be driven from the motor-shaft in order that the control shall be automatic.

My invention, however, comprehends a rotating rheostat controlled in any desired in anner. I may also point out that the means for moving the adjustable brush in proportion to the speed of the motor may be varied in many ways. The ball governor, as here shown, works upon a vertical shaft, so that gravity will move the balls in one direction, but a spring may be used to take the place of gravity, and the balls mounted in any other posi tion; also any arrangement of gearing may be used between the adjustable brush and the shaft for accomplishing the as the governor.

Having described my invention, I claim- 1. The combination of a rotary shaft, a rheostat-frame mounted thereon, a rheostat in said frame,a series of contacting-rill gs suitsame purpose ably insulated from each other and mounted upon the same shaft and forming the terminals respectively of the various sections of the rheostat, a brush constantly in contact with one of said rings,an adjustable brush adapted to make contact with any of said rings, and means for moving said adjustable brush.

2. The combination of a rotary shaft, a rheostat-frame mounted thereon, a rheostat in said frame,a series of contacting-rings suitably insulated from each other and mounted upon the same shaft and forming the terminals respectively of the various sections of the rheostat, a brush constantly in contact with one of said rings,an adjustable brush adapted to make contact with any of said rings, an electric-motor shaft and connections between said shaft and the adjustable brush whereby the latter is adjusted in proportion to the speed of the former, substantially as described.

In testimony whercof I subscribe my signature in presence of two witnesses.

THOMAS J. FAY. Witnesses:

WM. A. ROSENBAUM, FRANK S. OBER. 

